In the automatic coating of objects, in particular when painting vehicle bodies, not all of the coating medium exiting the application units lands on the object to be coated. Instead, so-called “overspray” is produced, the majority of which is discharged from the coating booth with the aid of an air flow and a relatively small proportion of which deposits on inner surfaces of the coating booth, but preferably on the outer surfaces of the application units and the adjacent regions of the handling device. The deposits have to be removed from these outer surfaces at regular intervals.
To facilitate this, previous practice has frequently been to provide the outer surface of the application unit with a protective film, for example of Vaseline, from the atomising region up to its mounting point on the handling device, i.e. in the case of a robot, for example, up to the wrist joint. This protective film then has to be removed manually from time to time and disposed of together with the deposited paint.
It is known in other fields of the technology to clean surfaces with the aid of CO2. This is advantageous in that the cleaned surfaces do not have to be additionally dried since the CO2 used for drying changes directly into the gaseous form by sublimation.
An object of the present invention is to provide a system of the type mentioned at the outset in which the cleaning of the application unit and adjacent regions can take place in as automated a manner as possible with relatively low material costs and relatively little manual effort.